Can Dune!

I hear it’s Sand Dune Week. Far be it from me to pass up a good geomeme!

I actually thought I had some more GigaPans of sand dunes, but it turns out the only ones that were primarily dune focused were the ones I shot at White Sands National Monument on New Years Eve of 2008. That’s just as well because these are indeed some beautiful barchans not so dissimilar from the Martian examples Brian highlighted in his contribution.

.

.

.

One thing you won’t find on a Martian dune is the vegetation such as the yuccas seen in this photo of a slumped slipface at White Sands. It you look at the color of the sand you’ll note that as white as it is, there is a patch toward the bottom right corner of something even whiter. Yes, that’s snow.

IMG_2424

Theme and Variations on Anorthosite and Labradorescence

Without a doubt, Siim Sepp‘s Sandatlas has already become one of my favorite new geoblogs. Back in the early heyday of geoblogging in 2007 it was a regular occurrence for the handful of geoblogers to highlight new geoblogs when they were discovered, and that’s something I’d like to get back into the habit of doing. Another thing that I really enjoyed in those days was when fresh geomemes would spontaneously appear and race through the geoblogosphere. It didn’t take much – an interesting post with a geologic theme that other geobloggers could echo with new variations. To some degree this sort of thing has been absorbed into the Accretionary Wedge, but often the Wedge format is too slow and cumbersome for a geomeme that ought to spread like wildfire. And so, when I saw Siim’s post about “Anorthosite and Labradorescence”this morning I knew I didn’t want to wait around for somebody to formalize this and turn it into a Wedge installment – I just wanted to post my reply right away.

And, of course, my reply comes in the form of a GigaPan three GigaPans that I shot this past August in the Adirondack Mountains of upstate New York. Back in early 2010 while I was doing a daily deskcrop/outcrop series on this blog, my ninth installment in that series was a series of photos of a roadcut along NY state highway 3 – the “Anorthosite Highway”. Those photos highlighted anorthosite and its labradorescence in its natural habitat, and, in many ways, they were the immediate precursor to my GigaPanning. Ever since I first got started using Google Earth I’ve wanted to recreate virtual field experiences through immersive photographic techniques. This began with basic panoramic photography and QTVRs and eventually came to fruition with GigaPans. Even so, GigaPans still have their own limitations. The series of GigaPans you see below would ideally be seamlessly nested into a single zoomable sequence, taking one all the way from the outcrop scale (top) to the macro scale (bottom). Unfortunately, there’s still no way to seamlessly merge GigaPan views together – at least, not yet…

.

.

.

There are actually lots of interesting things to see when one zooms in on these GigaPans. The focus on the Wide view is not crisp at full zoom, though one can still make out cleavage reflections on large plagioclase laths in that view. Berti and Edi stand in in the outcrop Detail view to give a sense of scale (Edi is about 10cm tall). Finally, in the Macro view one can make out many details of the mineralogy only hinted at in the previous two views. In addition to the labradorescence (or opalescence, as it’s sometimes referred to in the Adirondacks), there are some nice garnet coronas between plagioclase and pyroxene crystals to remind you that while these rocks have an igneous origin, they also experiences the joy of a good metamorphic episode in the granulite facies.

labradorescence
Two details from the macro GigaPan illustrating labradorescence (or opalescence).
Opalescence

Recording a Geology Office Hours Google+ Hangout

A number of geologists have commented on the value of using Google+ Hangouts for education. Google has indicated that eventually Google+ users will have the opportunity to record and save Hangouts to YouTube, but this capability is not yet implemented as part of the Google+ platform. I’ve been contemplating how to get around this restriction for a couple of weeks and after a couple of failed attempts, I finally cracked the nut last week. Recently I was asked if I would share my method for recording Hangouts – I’m happy to oblige.

The basic method I’m using employs two Google+ accounts on two computers, and the recording is done using Camtasia Studio. From my primary computer I begin the Google+ Hangout with Extras from my primary Google+ account. On the second computer I first mute the speakers, then join the Hangout with my secondary Google+ account. As I’m joining the hangout with my secondary account, I also mute its audio and video input (in the “Green Room” screen). (Muting all of these is important to prevent echoes and feedback.) Next, I begin recording the full screen with Camtasia Studio on the secondary computer – the recorder should be set to record system audio, but not microphone input. At this point, my secondary G+ account on the recording computer is acting as a “silent partner” monitoring and recording, but not contributing to the conversation. I am now free to turn back to the first computer and my primary Google+ account to conduct the Office Hours conversation. Nothing else needs to be done until the Hangout is concluded, when I simply stop the recording and exit both hangout windows. At this point it’s just a matter of editing the recording (if necessary) and converting the recording to an mp4 file and then uploading this to YouTube. I should note that there may be other/better methods that only use a single account or computer, but I’m satisfied that the method I’ve described works well enough for me. Don’t hesitate to ask in the comments if you’ve got any questions.

Double Exposure

Here’s a pair of GigaPans I shot this past summer at Kakabeka Falls, west of Thunder Bay, Ontario. Before I explain why I shot this scene twice, take a few minutes to explore the GigaPans and compare and contrast the two scenes. I’d be interested in your thoughts (please comment, below) on which is the more pleasing image and why you felt the way you did about them.

.

.

I’ve shot pairs of GigaPans before, but the goal previously was to combine two adjacent shots into an anaglyph GigaPan. This pair of GigaPans was shot from exactly the same spot, with a different intent. I used this pair of shots to try to expand my photography horizons, by shooting one (top) with the normal exposure settings I’d choose for most shots, but the second (bottom) with a very slow shutter speed to try to capture a more dreamy appearance in the waterfall (there’s probably a proper photographic term for that and I’d appreciate it if someone would let me know what it is). I also changed the framing a bit the second time round, to capture a slightly wider overall field of view, with the intent of doing a better job of framing the falls, as well. So the question to you, the viewer is: which do you like better? Let me know in the comments.

Cut the Schist…

… and you may see a cross section thru some lovely garnet porphyroblasts such as these. This was actually one of my earlier attempts at macro GigaPan photography, and at the time I really didn’t have the right lens combination to do this micaceous marvel justice. Nonetheless, I have it on good authority that this is going to be a pretty schisty weekend in the geoblogosphere, so I figured that this would be a fitting early contribution.

.

Introducing Students to Geologic Time

A couple weeks back, before I had figured out how to record Google+ Hangouts, one of our Monday afternoon Geology Office Hours discussions took an unexpected turn toward a discussion of how to teach students about geologic time in the most effective way, given a range of secular and religious backgrounds. This discussion, though not recorded, was faithfully reflected in a blog post by Dana Hunter, and that in turn inspired another thoughtful blog post by Tim Sherry. Since I just discovered Tim’s blog Up Section this week and added it to my Geoblogosphere list, I had the opportunity to come across his post on the subject for the first time today.

Toward the end of Tim’s post he asks:

What evidence can we present to show how we know rocks are really old? Show pictures of zircons? Well, then you’re talking about radioactive decay and isotopes, way too advanced for elementary school. Maybe show a sedimentary rock and talk about how it formed into it’s present form? Any elementary teachers out there with experiences/insight they’d like to share?

I answered in Tim’s comments, but I wanted to record that answer here and elaborate on it a bit.

The way I approached introducing geologic time with my Intro Geology classes was to mirror James Hutton‘s likely line of thought. Begin with Steno‘s Laws (Superposition, Original Horizontality, Lateral Continuity). These all make intuitive sense, thus don’t raise any hackles. Then apply them in a view of the strata of the Grand Canyon (or some local exposure of relatively flat-lying sedimentary rocks); no discussion of absolute ages yet, just make sure they get the principles of relative age dating.

187-8735_IMG
Horizontal Strata, Goosenecks of the San Juan River, southern Utah

.

Next, introduce them to Hutton’s angular unconformity at Siccar Point. Work them through the types of rocks (sandstone, shale) and discuss geologic environments and processes by which sand grains are first weathered and broken down from larger rocks, then eroded, transported, and deposited. Then there’s burial and later, the process of lithification. Finally some tectonic event causes these layers to be tilted. But that’s not all; you have to erode all the overlying rock so that they get back to the surface as tilted rocks. And then, in order to form the rocks above the unconformity surface you have to do all that over again!

DSC01198
Hutton’s Angular Unconformity at Siccar Point, Scotland
Photo by Meg Stewart, used under a CC BY-SA License

.

The coup de grâce is explaining Hutton’s understanding of Hadrian’s Wall. It was built by the Romans in the second century AD, and Hutton would have known this from written histories. By the time Hutton sees the wall in the 1780s its age is somewhere between a quarter and a third of the entire earth’s history by a Creation = 4004BC perspective. And yet it still stands. Yes, it’s overgrown and many boulders have fallen out of the wall, but they’ve hardly begun their process of weathering down to sand.

Hadrians Wall
Hadrian’s Wall, Scotland
Photo by Walt Jabsco, used under a CC BY-NC-ND License

.

Now think back to all the geologic events that had to occur for the Siccar Point unconformity to have formed, and with this single insight into the rates of geologic processes, it should immediately be clear how Hutton was able to apply naturalistic explanations to break free of the Biblical literalist interpretations of his time, and not at all shocking that he would make the even greater leap to “… no vestige of a beginning, no prospect of an end…”

Basin & Range

It was my good fortune this morning to catch sight of a timely tweet by Alexandra Witze that led me to not one, but two great interviews of John McPhee. The one Alexandra’s tweet pointed to was certainly interesting, but the longer interview, by McPhee’s former student Peter Hessler in the Paris Review, was an even deeper and more wonderful glimpse into McPhee’s writing method. As such, it is a most timely and insightful source of inspiration for those of us partaking in Anne Jefferson’s #sciwrite challenge. Even though I ended up spending the better part of the afternoon soaking in the interviews rather than #sciwriting, like had intended to do, I feel that I wasted not a moment of that time. If that is not recommendation enough, allow me to quote a choice section wherein McPhee describes his own process of writing:

It may sound like I’ve got some sort of formula by which I write. Hell, no! You’re out there completely on your own—all you’ve got to do is write. OK, it’s nine in the morning. All I’ve got to do is write. But I go hours before I’m able to write a word. I make tea. I mean, I used to make tea all day long. And exercise, I do that every other day. I sharpened pencils in the old days when pencils were sharpened. I just ran pencils down. Ten, eleven, twelve, one, two, three, four—this is every day. This is damn near every day. It’s four-thirty and I’m beginning to panic. It’s like a coiling spring. I’m really unhappy. I mean, you’re going to lose the day if you keep this up long enough. Five: I start to write. Seven: I go home. That happens over and over and over again. So why don’t I work at a bank and then come in at five and start writing? Because I need those seven hours of gonging around. I’m just not that disciplined. I don’t write in the morning—I just try to write.

Seriously, go and read that Paris Review interview as soon as you can. You won’t regret it.

I leave you with a composition of my own on the Basin & Range…

.